0 . Stochastic Market Sharing , Partial Communication and Collusion

This paper analyzes the role of communication between firms in an infinitely repeated Bertrand game in which firms receive an imperfect private signal of a common value i.i.d. demand shock. It is shown that firms can use stochastic, inter-temporal market sharing as a perfect substitute for communication in low demand states. Therefore, partial communication in high demand states is sufficient to achieve the most collusive, full communication outcome. And partial communication in low demand state does not improve on the equilibrium without communication. Communication in high demand states allows firms to coordinate their pricing, choose the most efficient uninformed price and avoid price wars. I demonstrate that, under some conditions, consumers are better off with communication among colluding firms. * Department of Economics, University of Auckland Clasificación JEL: L41, L13, D82